Generally, in a fuel supplying device to the internal combustion engine, there are two types of fuel supplying methods, one of which has return pipe for returning the fuel remained in the fuel supplying device after injection of the fuel to a combustion chamber of the engine, the other of which has not the return pipe for returning the fuel remained in the supplying fuel device.
Especially, the returnless type of fuel supplying method supplies the fuel supplied from a fuel pump by operation of the fuel pump to a fuel rail after the pressure of the fuel is constantly regulated by a fuel regulator. Then the fuel of the fuel rail is injected to the combustion chamber of the internal combustion engine through a fuel injector.
As shown in FIG. 4 and FIG. 5, the typical structure of the fuel injector comprises a body 100 having a supplying port 110 through which the fuel having constant pressure is supplied into the body 100 and a nozzle port 120 through which the fuel is injected into the combustion chamber of the internal combustion engine.
In the body 100 of the fuel injector is mounted a spool 31, which is moved by operation of a solenoid 30 and supported by a spring 32 to selectively opens and closes the fuel passage 130 formed in the body 100.
The fuel is supplied into the body 100 of the fuel injector under the state that the spool 21 closes the fuel passage 130. Then, at injection time, the spool 31 is moved to the inside of the solenoid 30 to open the fuel passage 130 and the fuel in the fuel passage 130 is injected through the end of left part of the nozzle port 120.
As shown in FIG. 5, the prior fuel injector opens the fuel passage 130 under the state that the supplying port 110 is opened even the injection time, so the fuel pressure in the fuel rail is instantly varied. As the result of that, the fuel amount injected into the combustion chamber of the internal combustion engine is reduced, and then the engine is hunted and the output of the engine is decreased.
While, in U.S. Pat. No 4,925,112 is disclosed a fuel injector, which has a pair solenoid coils aligned along a common axis between an armature that serve as fuel metering valve and an armature that operates a charge delivery valve.
And in U.S. Pat. No 5.979.786 is disclosed a fuel injection apparatus, which has a single solenoid coil that controls the movement of a first and second armature respectively. Each armature is connected to a valve element for controlling a fuel supply and for controlling the delivery of the charge respectively.
Then, the fuel injectors according to the above U.S. Patents are to control the flow of the fuel and the air simultaneously. Therefore, the construction of the fuel injector is very complex and have too much number of parts in their inside.